Rifle twist.

[Johnny_Revolver]

Okay, my .223 has a rifle twist of 1 - 12, but I am told to use a 64 grain projectile I need faster rifling like 1 -10... why is so? What would happen if I use the heavier projectiles?

Originally Posted by Logansdad

I was told that the Viet Nam round was a 70 grain bullet exiting a 20 inch barrel with a 1 turn in 12 or 14 inch twist rate. I was also told that the SS109 round is a 62 grainer optimized for a 20 inch barrel with a 1 turn in 7 inch twist rate. I was also told that the 55 grain projectile was optimal for a 1 turn in 9 inch twist and what the Military was going to standardize upon for regular line troops.
What is the real story ?

Originally Posted by Logansdad

Oh yeah...the 70 grainer wasn't supposed to stabilize....allowing it to "Keyhole" or tumble.

[Johnny_Revolver]

Thanks L.D. I was figuring it was something like this.

.223 Remington

During the mid-1950's, three .224" caliber cartridges were in contention to succeed the 7.62mm NATO as our primary military cartridge. They were the .222 Winchester, .224 Springfield, and.222 Special, the latter developed by Gene Stoner of Armalite. All were stretched versions of the .222 Remington cartridge. The .222 Special won out over the other two and soon became known as the .223 Remington.

According to a popularity chart published by RCBS, based on reloading die sales, the .223 Remington is our most popular .224" caliber centerfire, ranks second only to the .30-06 among all rifle cartridges, and twelfth among all handgun and rifle cartridges. The reason for such popularity becomes quite obvious when one works with the .223 Remington. The .223 shoots flat enough for 300 yard varmint shooting and yet its relatively small appetite for powder is easy on rifle barrels, on the shoulder, on the budget, and muzzle blast is comparatively mild. Neither is the .223 choosy about the diet it is fed, a number of powders produce top performance and superb accuracy, including H335, H4895, BL-C(2), IMR-3031, IMR-4895, and W-748.

Match grade, hollow point bullets are fine for target shooting with the .223 but they often don't open quick enough for the explosive expansion needed for varmints such as groundhogs humanely at the longer ranges. Best bet for shooting varmints with this cartridge are the Speer TNT, Nosler Expander, Hornady Super Explosive (SX), and Sierra Blitz bullets, with their soft lead cores and extremely thin jackets. For competitive shooting, the Hornady 68 grain and the Sierra 69 grain hollow point bullets are excellent wind buckers but require a rifling twist rate of 1-7 to 1-8 inches for stabilization. Most sporting rifles have rifling pitch rates of 1-12 or 1-14 inches.

from http://www.reloadbench.com/cartridges/223.html

"Err, Bob? You might want to give the manufacturer a call. I think there's something wrong with this rifle. It shoots all over the place." My boss at the time didn't want to hear those words, but I showed him the targets and I was right-the rifle was throwing its shots all over the paper at 100 yds. Some bullets were even keyholing so badly that they were hitting nearly sideways.

"Let me see that," he said.

I handed him the gun.

"Here's the ammunition I was using, too."

Bob looked at the rifle that was chambered for .22-250 Rem. and then at the ammunition. Heavy bullets in .22-cal. centerfires were just coming into vogue, and I had chosen loads with bullets weighing 60 grs. or more to test the gun for accuracy.

"You know this rifle has a 1:14" twist, don't you?" Bob asked.

Golly, I felt dumb. I should have known better. That rate of twist is too slow to stabilize long, heavy bullets, and that is why competitive shooters using AR-15-style rifles in .223 Rem. cal. use twists as fast as 1:7" to stabilize the long, heavy bullets used for long-range shooting.

Rifling rate of twist and bullet weight-more correctly bullet length-have an important relationship that influences bullet stability. A stable bullet is accurate; an unstable one is not.

Generally, shooters need not be concerned with the bullet length/rate of twist relationship as most factory barrels have a rate of twist intended to work with the range of bullet lengths generally offered for each specific chambering. It's when shooters experiment with extreme bullet weights that are long for the caliber or custom rifles, however, that rate of twist is most important.

A method for estimating correct rate of twist was developed prior to World War I by Sir George Greenhill. His formula states that the product of the rate of twist and the bullet length in calibers should equal 150. For example, the optimum rate of twist for Sierra's .30-cal., 200-gr. MatchKing would be computed as:

(t) (1) = 150

Where: t = rate of twist

1 = bullet length in calibers (1.405/.308)

t=150/4.56

t=32.89 calibers

To convert calibers to inches, multiply by the bullet diameter. In this case, (32.89)(.308)= 10.1 inches.

According to Greenhill's formula, then, the proper rate of twist for the Sierra .30-cal., 200gr. MatchKing is 1:10". That said, and with all due respect to Greenhill, some long-range shooters are experimenting with slower rates of twist.

Still, most of us will be perfectly satisfied with the standard rates of twist barrel makers use. But if you do have a problem with keyholing or poor accuracy, and you can't pin it down to any other lighter/shorter bullet before you write off a gun as having something wrong with it.

Scott E. Mayer, Shooting Editor

Copyright National Rifle Association of America Jan 2003
Provided by ProQuest Information and Learning Company. All rights Reserved

from http://www.findarticles.com/p/articl...87421#continue

[Johnny_Revolver]

I read somewhere that .223 is Australia`s best selling calibre, I would have thought .243, but I suppose all the pro roo shooters useing .223 now is a factor. For the better part of what I shoot, the .223 is humane: hit it in the head or miss or dont bother. Okay for pigs a head shot might not be the best idea, hopefully my new .308 is handy then and even more hopefully sighted in correctly. I was sceptical at first but now I am quite enthusiastic about .223 rem as a round and look forward to handloading some real accuracy.

[Mick]

Johnny, I've got a sako vixen chambered in .223, it's an excelent rifle, I had never thought of it as a good gun for shooting red deer with until the other day, I shot a stag at about 250 metres, through the shoulder, heart lung shot, with 55gr remington factory soft tips.
Now I don't normaly use this rifle for anything bigger than 'roo's, but it was the gun I had with me at the time. I was quite impressed.

[Johnny_Revolver]

Mick: very impressive old son! Look if I saw a pig the size of a bullock and I only have my .223 with me, guess what I`ll do??

[auspighunter]

i dont think i will upgrade the 222 for a 223 maybe once our barrel wears out but shes only had about 3000 rds in the last 15 yrs

[Johnny_Revolver]

If someone offered me a good .222 for a good price, I wouldnt be afraid to buy it in theory, but given the choice ( like I was for a new rifle ) I`d pick .223, its the way of the future really. I just need to be VERY carefull to not mix rounds if I got shooting with someone with a .222... could get ugly.

[auspighunter]

when it comes time to put a new barell on it i will got to 223 i can pretty much get ammo for free
but yeah 222s are great we have killed more pigs wif 222 than the 308 its much more comforatble to shoot and less expensive for hunting rounds

but im getting myh 22-250 in a week or so , looks like the 222 might not get much of a look in ne more

[utahvarminter]

http://www.ammo-oracle.com/body.htm

go to this-- scroll down a bit, but this page should answer any .223/5.56 ammo/rifling questions.

[Stiletto]

GRR beat me to it

Anyway, some other useful info:

A 1:12 twist rifle shouldn't be used with anything heavier than about 55gr (original M16s and M16A1s were 1:12 or 1:14, can't remember).

1:9 is good up to about 68gr, and works fine down to the 40gr bullets (for a CZ 527, anyway).

1:7 is good for all of the heavier stuff, but begins to show degradation for 55gr bullets, so stick to 60gr and up.

[auspighunter]

how would that work wif my 22-250
1-14 twist
u recon i could use 60grs in it
i have a speer loading book that has the same barrel length and twist wif 70gr speer in it